Eastern Oak Forests Disappearing

7-2-96
University Park, Pa. -- While rain forest protectors are concerned with the rampant clear-cutting of those forests, some foresters in Pennsylvania think cutting and controlled burning may be the only way to perpetuate the area's oak forests.

"Eight or so years ago when I suggested setting fires, there was a very negative attitude toward the idea," says Dr. Marc D. Abrams, associate professor of forest ecology and physiology. "Now there are some foresters who think we should have trials of controlled burning to see how it affects the forest composition."

Oak forests occur throughout the United States and in the east, they have been a major economic resource since the 1700s. In Pennsylvania, while the Allegheny Plateau is populated with northern hardwoods -- maple, cherry and birch, the lower two thirds of the ridge and valley area is mixed oak forest. With less clear-cutting of oak going on and nearly absolute control of naturally occurring fires, the oak forests are converting to birch, maple and cherry. According to Abrams, oaks just can't compete.

"Oak is one of the most important woods for cabinet making, flooring and furniture," says Abrams. "It is currently worth more per board foot than red maple."

But Pennsylvania's oak forests and those in other areas are becoming northern hardwood forests. Changes in lumbering practices in the past 40 years and the early 1900s decision to stop all fires on public lands, have allowed forest succession to progress.

"Oak is an early successional species," says Abrams. "As long as other species are prevented from getting hold, oak persists, but once other species take over , it is very difficult to get oak to come back."

If an oak forest is cut for lumber, there are saplings and trees that regenerate. If fire burns through an oak forest, trees two to three inches in diameter can usually withstand the fire and even if the forest top is killed, the oak forest regenerates.

But, if the understory of the forest has converted to maple, birch and cherry, clear-cutting or a fire will cause these hardwoods to come back. Oaks like open canopies and so maple, birch and cherry tend to crowd them out and suppress sprouting of saplings in the understory.

"We've studied mature oak cut in the 1930s and 1940s and oak forests with maple and cherry," says Abrams. "When these two types of forest are cut, its more than likely that maple and cherry will come back."

Not only commercial activities will be hurt by reduction of oak forests, but also wildlife will also be affected.

"White-tail deer will eat the foliage of most tree species and they certainly eat oak and acorns," says Abrams. "But frequently, when oak disappear, mountain laurel and philodendron take over and deer won't eat these species at all."

In general, acorns are near the top of the food list for wildlife, especially in winter. Not only deer, but ducks, quail, racoons, bear and turkeys eat large quantities of acorns. A shift to hardwood forest could impact these animal populations.

Oak forests, although early in the natural succession of eastern forests, have persisted through prehistoric and historic times, because natural fire, perhaps Native American fires, and lumbering have combined to retard succession.

Abrams, a faculty member in the College of Agricultural Sciences, suggests that a reintroduction of fire might mitigate the problem. He does not suggest we let naturally occurring fires to burn uncontrolled, but rather that fires be planned and set to promote the regrowth and establishment of oak forests.

"Once there is adequate oak in the forest, there is a good likelihood that oak will come back after cutting," says Abrams.

*aem*

EDITORS: Abrams is at (814) 865-4901 (office).

Contacts:
A'ndrea Elyse Messer (814) 865-9481 (office)/(814) 867-1774 (home)
aem1@psuvm.psu.edu or 76520.3240@compuserve.com

Vicki Fong (814) 865-9481 (o)/814-238-1221 (h) vyf1@psu.edu